View Full Version : How to make a Neutral gear with BallShifters?
TheFrozenSlink
09-01-2014, 23:10
Our team was planning on possibly making a slingshot style launcher, where a motorized winch pulls back and arms our cannons and then we would shift into a neutral gear to disengage the winch and, and the ball would be fired, similar to 1114 in 2008 (Im sure you've seen a lot of them in the past 5 days).
I was wondering how difficult it would be to convert the 3 Cim BallShifters our team ordered so it would have a neutral gear, or if there is a better way to accomplish the same task, that wouldn't require taking apart our gearboxes?
waialua359
09-01-2014, 23:35
Our team was planning on possibly making a slingshot style launcher, where a motorized winch pulls back and arms our cannons and then we would shift into a neutral gear to disengage the winch and, and the ball would be fired, similar to 1114 in 2008 (Im sure you've seen a lot of them in the past 5 days).
I was wondering how difficult it would be to convert the 3 Cim BallShifters our team ordered so it would have a neutral gear, or if there is a better way to accomplish the same task, that wouldn't require taking apart our gearboxes?
Make sure you figure out a hard stop to prevent backdriving, once loaded.
cadandcookies
09-01-2014, 23:54
I was wondering how difficult it would be to convert the 3 Cim BallShifters our team ordered so it would have a neutral gear, or if there is a better way to accomplish the same task, that wouldn't require taking apart our gearboxes?
Probably want to look at the page again-- they ship with assembly required, so any modifications can be made while putting them together.
You could definitely do it outside of the shifter-- basically add an outside stage with a dog-style release (a la Simbot SS). Inside might take a little more creativity though.
We are working on a similar setup with the 2-CIM shifter. My concern currently is the level of force applied from the 60 psi pancake as compared to a long-throw lever arm. We may spring load it, since significant rotational load will be on the gear we want to disengage. We'll find out tomorrow...
kevin.li.rit
10-01-2014, 01:01
Our team was planning on possibly making a slingshot style launcher, where a motorized winch pulls back and arms our cannons and then we would shift into a neutral gear to disengage the winch and, and the ball would be fired, similar to 1114 in 2008 (Im sure you've seen a lot of them in the past 5 days).
I was wondering how difficult it would be to convert the 3 Cim BallShifters our team ordered so it would have a neutral gear, or if there is a better way to accomplish the same task, that wouldn't require taking apart our gearboxes?
It should be as simple as removing one of the output gears on the shifting stage and repacking it with a spacer. This way it has no gear to engage when shifted in one position (neutral).
mman1506
10-01-2014, 01:11
If you don't want to replace a gear you can get a pancake cylinder with a stroke that will shift into neutral position (in between the high and low gear). An even easier way would be adding a spacer to the pancake cylinder shaft to limit travel.
craigboez
10-01-2014, 01:13
There are 6 balls within the ball shifter, three for each of the two shifting gears that engage. If you remove the three balls for one of the gears, that gear will never engage, effectively leaving you with a neutral position.
The easiest way to do it is to not install the drive gear for the low gear stage and put a spacer or even a much smaller diameter gear of the same width in its place.
You can do it by removing gears and/or balls from the driven shifter cluster but the spacer trick is quick and simple if you want to keep the high gear.
Answer42
10-01-2014, 02:44
Our team was planning on possibly making a slingshot style launcher, where a motorized winch pulls back and arms our cannons and then we would shift into a neutral gear to disengage the winch and, and the ball would be fired, similar to 1114 in 2008 (Im sure you've seen a lot of them in the past 5 days).
I was wondering how difficult it would be to convert the 3 Cim BallShifters our team ordered so it would have a neutral gear, or if there is a better way to accomplish the same task, that wouldn't require taking apart our gearboxes?
Did you order 3 cim ball shifters just for this task? Seems kinda overkill to me.
GarrettF2395
10-01-2014, 04:05
There are 6 balls within the ball shifter, three for each of the two shifting gears that engage. If you remove the three balls for one of the gears, that gear will never engage, effectively leaving you with a neutral position.
My team did this at Thursday meeting for our prototypes. However, the transmission had some difficulty properly engaging and disengaging.
We were running it without load and shifting by hand.
We're going to take it apart tomorrow and see if we notice anything buggy in the system.
If that still doesn't work, plan B is to create a neutral for our super shifters.
Brandon Holley
10-01-2014, 11:00
You can do it by removing gears and/or balls from the driven shifter cluster but the spacer trick is quick and simple if you want to keep the high gear.
Along the same lines- just remove the balls from the high gear so that the plunger has nothing to clutch into for that gear set.
-Brando
James Tonthat
10-01-2014, 11:39
Along the same lines- just remove the balls from the high gear so that the plunger has nothing to clutch into for that gear set.
-Brando
You could machine teeth off the gears so that they never mesh. ;)
TheFrozenSlink
10-01-2014, 18:32
Thanks for the help, Ill be sure to try your suggestions whenever the thing gets here... We ordered it before kickoff and it still isn't here!:eek:
TheFrozenSlink
10-01-2014, 18:34
Did you order 3 cim ball shifters just for this task? Seems kinda overkill to me.
No, I agree that would be a bit excessive haha, we ordered them for our drivetrain.
Paul Copioli
10-01-2014, 19:07
You can simply remove the input gear for the high speed gear stage. That is the easiest way.
We are testing this now to see the max loading the ball shifter can still shift into neutral. My theoretical calculation indicates in excess of 400 lbs in a 2" diameter winch.
You can simply remove the input gear for the high speed gear stage. That is the easiest way.
We are testing this now to see the max loading the ball shifter can still shift into neutral. My theoretical calculation indicates in excess of 400 lbs in a 2" diameter winch.
Paul, I can't tell you how relieved we are to see you answering this question.
My students tell me that taking the high gear input results in no interface with the CIM. We will test your suggestion and see if we can figure out how to make this work. Let us know what you come up with too, if you get a chance.
Thanks!
Paul Copioli
10-01-2014, 21:23
Paul, I can't tell you how relieved we are to see you answering this question.
My students tell me that taking the high gear input results in no interface with the CIM. We will test your suggestion and see if we can figure out how to make this work. Let us know what you come up with too, if you get a chance.
Thanks!
Your students are correct. It has been a long week.
Attached are the 2 cross sections:
The 2 and 3 CIM. As you can see, if you remove the high speed cluster, then you will have no CIM motor input. You have 3 choices: (1) remove the low speed cluster, (2) remove the high speed ball gear, or (3) remove the balls from the high speed part of the ball shifter output. Personally, I would remove the balls as putting the shaft together is easy IF you have snap ring pliers.
kevin.li.rit
10-01-2014, 22:32
Snap ring Pliers? for my team I've invested the 3 dollars for this (http://www.harborfreight.com/snap-ring-pliers-with-interchangeable-heads-60531.html) pair.
Team1339
10-01-2014, 23:05
Let me be clear (with pictures). There are two versions of the Ball Shifter: last year's 2 CIM version and this year's 3 CIM. Your students are correct for the 3 CIM, but you do not need the 3 CIM version for this activity. The reason is the 3 CIM Ball Shifter design changes(besides adding another CIM) were specifically for use in a WCD drive base and to increase the amount of spreads available.
For the neutral application none of this matters and a 2 CIM is fine.
Attached are the 2 cross sections
The 2 CIM. As you can see, I removed the high speed input gear and you have a neutral.
The 3 CIM. As you can see, if you remove the high speed cluster, then you will have no CIM motor input. You have 3 choices: (1) remove the low speed cluster, (2) remove the high speed ball gear, or (3) remove the balls from the high speed part of the ball shifter output. Personally, I would remove the balls as putting the shaft together is easy IF you have snap ring pliers.
With all that said, I would just use the 2 CIM shifter.
Hello there, previously mentioned team member here.
Unless I am missing something, what you say is not true. The only gear that actually interfaces with the 2 Cims on either side is the gear that you suggest removing. The power is transferred to the other stage through the hex axle, however, it does not interface with the Cims directly. Therefore, your only option to create a idler stage would be to remove the low stage gear.
Paul Copioli
10-01-2014, 23:07
Look at the edited post.
Team1339
11-01-2014, 12:23
Look at the edited post.
Okay, thank you! We really appreciate everything that you have been doing for the teams, especially responding on the these forums, it is pretty cool to interact with you guys.
TheFrozenSlink
11-01-2014, 19:17
Your students are correct. It has been a long week.
Attached are the 2 cross sections:
The 2 and 3 CIM. As you can see, if you remove the high speed cluster, then you will have no CIM motor input. You have 3 choices: (1) remove the low speed cluster, (2) remove the high speed ball gear, or (3) remove the balls from the high speed part of the ball shifter output. Personally, I would remove the balls as putting the shaft together is easy IF you have snap ring pliers.
Wow thank you very much, for the response, and participating in BuildBlitz , it really helped our team, and many others, to get a good start to this season.
On a slightly unrelated side note, would you know when are the shifters going to actually ship? We ordered them the same weekend of the new product launch (they said they would ship before kickoff) , and when we asked Vex customer support they tell us they will ship tomorrow. This would be alright, if they hadn't been telling us that for the past week and a half, every time we ask :confused: , is this happening with many teams or is it ours?
Paul Copioli
11-01-2014, 19:52
Wow thank you very much, for the response, and participating in BuildBlitz , it really helped our team, and many others, to get a good start to this season.
On a slightly unrelated side note, would you know when are the shifters going to actually ship? We ordered them the same weekend of the new product launch (they said they would ship before kickoff) , and when we asked Vex customer support they tell us they will ship tomorrow. This would be alright, if they hadn't been telling us that for the past week and a half, every time we ask :confused: , is this happening with many teams or is it ours?
Yeah, sorry about that. We had an inventory snafu here in Greenville, but all of the shifter components should be in stock this week and they will definitely ship in time for the weekend. I will have to check on Monday when I am in the office.
Paul
TheFrozenSlink
11-01-2014, 20:01
Yeah, sorry about that. We had an inventory snafu here in Greenville, but all of the shifter components should be in stock this week and they will definitely ship in time for the weekend. I will have to check on Monday when I am in the office.
Paul
Yay :D! I really had to twist some of our mentors arms to let us buy them, they would probably have my head on a stick if they didn't come soon haha
holygrail
12-01-2014, 18:50
We spent some time this weekend working on modifying the ball shifter to use as a winch. We removed the three balls from the high gear and it seems to work well as a neutral gear since it can no longer engage the high gear. Thanks for the advice on this thread on how to do it. It wasn't as hard as I expected and it was cool for the students to see the inner workings of the gearbox.
One question though. It seems like there is quite a bit of natural resistance in the gearbox even when it is in neutral. We haven't hooked it up to a winch under tension yet, but it seems like it might slow things down quite a bit even when it does kick into neutral gear.
Is the tension on a bungee powered catapult enough to overcome that resistance and still get a powerful, consistent shot?
Paul Copioli
12-01-2014, 19:03
We spent some time this weekend working on modifying the ball shifter to use as a winch. We removed the three balls from the high gear and it seems to work well as a neutral gear since it can no longer engage the high gear. Thanks for the advice on this thread on how to do it. It wasn't as hard as I expected and it was cool for the students to see the inner workings of the gearbox.
One question though. It seems like there is quite a bit of natural resistance in the gearbox even when it is in neutral. We haven't hooked it up to a winch under tension yet, but it seems like it might slow things down quite a bit even when it does kick into neutral gear.
Is the tension on a bungee powered catapult enough to overcome that resistance and still get a powerful, consistent shot?
I would remove that gear completely and just put a spacer in there. The only resistance you should have is the rolling resistance of the two bearings and the resistance between the bushing in the remaining gear and the shaft. This should be nothing compared to the load the bungee (or whatever you are using) will be to shoot the ball.
Yeah, sorry about that. We had an inventory snafu here in Greenville, but all of the shifter components should be in stock this week and they will definitely ship in time for the weekend. I will have to check on Monday when I am in the office.
Paul
I see that the shifters are shipping out, thanks for that. How is the Versa Frame going?
BBray_T1296
12-01-2014, 19:49
Did you order 3 cim ball shifters just for this task? Seems kinda overkill to me.
"Over-kill is under-rated"
TheFrozenSlink
12-01-2014, 23:12
"Over-kill is under-rated"
That used to be our team's motto back in 2012, when we made a shooter that shot 70+ feet..ahh good times.
http://youtu.be/Eu9odIFwRHE?t=54s
Answer42
13-01-2014, 01:25
You can simply remove the input gear for the high speed gear stage. That is the easiest way.
We are testing this now to see the max loading the ball shifter can still shift into neutral. My theoretical calculation indicates in excess of 400 lbs in a 2" diameter winch.
That's awesome that you're providing this information.
You can simply remove the input gear for the high speed gear stage. That is the easiest way.
We are testing this now to see the max loading the ball shifter can still shift into neutral. My theoretical calculation indicates in excess of 400 lbs in a 2" diameter winch.
Paul: Just to confirm: Are you saying the recommended stock 3/4" air cylinder will shift the winch with the 400lbs load consistently / reliably or should we be upgrading the cylinder size ?
Having said that, I would be surprised if we are over 100lbs.
Thanks
Monochron
17-02-2014, 11:45
I would remove that gear completely and just put a spacer in there. The only resistance you should have is the rolling resistance of the two bearings and the resistance between the bushing in the remaining gear and the shaft. This should be nothing compared to the load the bungee (or whatever you are using) will be to shoot the ball.
We are seeing a great deal of resistance as well. For example, when a motor is not present in the gearing the shaft is very easy to turn with only two fingers. When a motor is present and the gearbox is in neutral (made by removing the low speed gear) the shaft can't be turned by hand by some of our smaller students and takes a good deal of force from anyone.
Is this normal behavior or are we missing something?
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